Diving sinkers are used in ocean fishing and in great lakes fishing to carry the bait down to deep feeding fish. Typical prior art diving sinkers are disclosed in my co-pending U.S. Pat. application Ser. No. 407,341, now U.S. Pat. No. 3,844,059, and in U.S. Pat. No. 3,643,370 to Cook et al. In both disclosures, a flat plate has means on its rear end for connecting a fish bait thereto and has a link swingably attached to the front portion of the plate with an eye on the link for attachment to a trolling line. In the sinker of my U.S. Pat. No. 3,844,059, the link is detachably held in a position to cause the flat plate to dive by a spring wire extending forwardly and upwardly from the rear of the flat plate. A hook on the end of the spring detachably engages an eye on the end of the link. When a fish strikes the bait, the striking force applied to the rear of the plate causes the link to detach from the spring and allows the link to swing forwardly to a position which causes the flat plate to rise. In this diving sinker, the amount of force necessary to detach the swingable link depends on the strength of the spring and is not adjustable. Furthermore, assembly is time-consuming.
In the diving sinker of U.S. Pat. No. 3,643,370, the swingable link has a small ball on its end which is detachably engaged in a pair of jaws on a flexible support which extends upwardly from the flat plate. When a fish strikes the bait, the striking pressure causes the ball to snap out of the jaws and permits the link to swing to a position which causes the flat plate to rise. An adjustment screw is threadably attached between the jaws to adjust the force required to snap the ball free. This diving sinker is adjustable, but it is inconvenient to use because the small size of the detachable ball and the jaws makes it difficult to snap the ball into the jaws, and the ball is on a loose hanging extension.